1. Field of the Disclosure
This disclosure generally relates to an image sensing device and, more particularly, to a color image sensor and arrangement of color filters and operating method thereof that may eliminate the influence of infrared light components by post-processing.
2. Description of the Related Art
In the conventional color image sensor, every pixel of an image sensing array is overlaid with a red color filter, a green color filter or a blue color filter to allow the pixels under the color filters can only detect the energy of specific spectral range.
For example, FIG. 1 respectively shows the normalized wavelength response of red, green and blue color filters. It is clear from FIG. 1 that IR light over the wavelength of about 800 nm can still penetrate the red, green and blue color filters. As a pixel is configured to detect light energy impinging on the sensing surface thereof and when the color filter covering thereon is not able to block the IR light effectively, the detected signal outputted by every pixel also contains the light energy of IR light components. For example, the detected signal of the pixel covered by a red color filter contains components of red light and IR light; the detected signal of the pixel covered by a green color filter contains components of green light and IR light; and the detected signal of the pixel covered by a blue color filter contains components of blue light and IR light. Particularly, when the environment further has an IR light source, the energy of IR light components in the detected signal may be larger than that of red, green or blue light components such that each light color may not be detected correctly.
The aforementioned IR light components may have obvious influence in some applications. For example, if it is desired to construct the spectrum of ambient light according to detect signals of red light, green light and blue light, a correct wavelength response may not be constructed due to the existence of IR light components.